First video documented presence of Mediterranean monk seal in Southern Apulia (Italy)

Sightings of Endangered monk seal (Monachus monachus) specimens have been increasingly reported along the coasts of its historic Mediterranean distribution over the last two decades, even from countries where the species was considered extinct for about half a century. These encounters have been documented and verified particularly along the coasts of the Adriatic-Ionian basin. The activities carried out in Salento (Southern Apulia, Italy) since 2012, engaging with local protected areas, authorities and different stakeholders (organizations, museums, universities, fishermen’s cooperatives and tourism sectors enterprises) allowed us to record and verify 10 monk seal sightings (from 2009 to 2014) in the area. However, the last sighting with photographic documentation dates back to 1973. In June 2017, after six years of monitoring and awareness of the territory, immediately after the sighting, we received a video evidence of such presence. The footage, and the resulting interview with the witnesses, documented the presence of a Mediterranean monk seal’s specimen, about 2 meters in length, along the coast of Tricase (Lecce, Apulia). This new event has a remarkable importance to the hypothesis that Salento and the Adriatic-Ionian basin might play an important role in the overall conservation of the specie

Input of various chemicals transported by Saharan dust and depositing at the sea surface in the Mediterranean sea

This paper reviews work on the role of Saharan dust as a contribution of various chemical to the Mediterranean basin. Both the magnitude and the mineralogical composition of atmospheric dust inputs indicate that eolian deposition is an important (50%) or even dominant (>80%) contribution to sediments in the offshore waters of the entire Mediterranean basin. The Mediterranean Sea is a semi-enclosed basin, that receives substances sporadically from the arid region of the Sahara desert. We considered the location and strength of source areas, the transport paths of material away from the desert, the number of Saharan dust transports per year, the way to be dust is deposited (wet and dry mode), the fluxes of Saharan dust, the nature of the material, and the contribution of nutrients to the sea surface. Estimates of atmospheric inputs to the Mediterranean and some coastal areas are reviewed. Model data for nutrients indicate that the atmosphere delivers the nitrogen and one-third of total phosphorus to the entire basin. Measured data in sub-basins, such as the Western Mediterranean and Eastern Mediterranean indicate an even greater proportions of atmospheric versus riverine input. New production supported by atmospheric nitrogen deposition ranges from 2–4 g C m -2 yr -1 , whereas atmospheric phosphorus deposition appears to support less than 1 g C m -2 yr -1 . In spite of the apparently small contribution of atmospheric deposition to overall production in the basin it has been suggested that certain episodic phytoplankton blooms are triggered by atmospheric deposition of N, P or Fe. Iron fluxes may be important in determining the nature and quantity of carbon fluxes from Fe-rich areas (like MED Sea), in addition to Fe-poor areas such as the extant Southern Ocean. A geophysiological model shows that iron removal from the photic zone does occur at a much higher rate than the conventional biological pump can account for and that this might release the risk of excessive phosphate scavenging

Saharan dust inputs to the W Mediterranean Sea: depositional patterns, geochemistry and sedimentological implications.

Data are presented for a number of parameters for aerosols and rainwaters collected at a station on Sardinia. The findings are interpreted with special reference to Saharan dusts, and are compared to other data on these dusts obtained from a variety of sites around the Mediterranean Sea. At the Sardinia site the particle size distribution of the Saharan outbreaks exhibits a bimodal structure, the two modes being between 1 and 2 µm and 20-25 µm. The presence of giant particles strongly affects the deposition velocities of the Saharan aerosols. Source markers for the Saharan dusts are palygorskite, kaolinite, calcite, dolomite and rounded quartz grains. The input of Saharan dust has important effects on the chemistry of the Mediterranean aerosols. These include: (i) increases in the atmospheric concentrations and sea surface fluxes of crust-controlled trace metals (e.g.; Al, Fe); (ii) decreases in the EFcrust values of non-crust-controlled trace metals (e.g.; Cu, Zn and Pb) in the aerosols, and (iii) changes in the solid state speciation of Cu, Zn, and Pb, which decrease their solubilities in sea water. The Saharan dusts also affect the composition of rainwater by raising the pH, following the dissolution of calcium, and by decreasing the solubility of trace metals such as Cu, Zn and Pb. Wet deposition controls the flux of Saharan dust to the Mediterranean Sea, but dry deposition can also be important. The dust transport occurs in the form of "pulses", and the annual dust flux can be controlled by few episodes of Saharan outbreaks; e.g. sometimes a single outbreak can account for 40-80 % of the flux. Saharan dust deposition fluxes range from 2 to 25 g m-2 (average; ~ 10) in the W Mediterranean between 39° and 42° N, between 6 and 46 g m-2 (avg. ~ 20) in the E Mediterranean, and 0.4 to1.0 g m-2 over the Alps on continental Europe. The present day Saharan dust fluxes (~ 1 mg cm-2 yr-1) account for about 10-20% of the recent deep-sea sedimentation in the Western Mediterranean (3-15 mg cm-2 yr-1)

Ship-Induced Depression Wakes and Shoreline Erosion

Shoreline retreat as an effect of ship wakes was studied in a navigation channel of the industrial port of Venice, Italy: the Malamocco -Marghera Channel. The investigation revealed unprecedented erosion rates, up to 4 m y , that determined a total loss of about 1.2 million of m of soil in the period 1970 -2015. This interaction between navigation and the channel margins must be considered in order to understand the past evolution of the central Venice Lagoon and for a sustainable management of the port traffic in the future sea -level rise scenario

Development of algebra algorithms for automated generation of grain-size distribution maps

The grain-size distribution of sediments is a fundamental characteristic in understanding the earth’s surface environments and an essential tool in classifying sedimentary environments. Grain-size data provide important information on the energy and dynamics of depositional environments and aid our understanding of sediment transport. Ternary diagrams (TD) are useful and conventional tools to classify sediments on the basis of relative grain-size (i.e., gravel, sand, mud or sand, silt, clay). The development of spatial modelling in a Geographical Information System (GIS) can assist in treating, computing and displaying sedimentological data, such as grain-sizes. The grain-size distribution of sediments is a fundamental characteristic in understanding the earth’s surface environments and an essential tool in classifying sedimentary environments. Grain-size data provide important information on the energy and dynamics of depositional environments and aid our understanding of sediment transport. Ternary diagrams (TD) are useful and conventional tools to classify sediments on the basis of relative grain-size (i.e., gravel, sand, mud or sand, silt, clay). The development of spatial modelling in a Geographical Information System (GIS) can assist in treating, computing and displaying sedimentological data, such as grain-sizes

Spatial and Temporal Changes of Tidal Inlet Using Object-Based Image Analysis of Multibeam Echosounder Measurements: A Case from the Lagoon of Venice, Italy

Scientific exploration of seabed substrata has significantly progressed in the last few years. Hydroacoustic methods of seafloor investigation, including multibeam echosounder measurements, allow us to map large areas of the seabed with unprecedented precision. Through time-series of hydroacoustic measurements, it was possible to determine areas with distinct characteristics in the inlets of the Lagoon of Venice, Italy. Their temporal variability was investigated. Monitoring the changes was particularly relevant, considering the presence at the channel inlets of mobile barriers of the Experimental Electromechanical Module (MoSE) project installed to protect the historical city of Venice from flooding. The detection of temporal and spatial changes was performed by comparing seafloor maps created using object-based image analysis and supervised classifiers. The analysis included extraction of 25 multibeam echosounder bathymetry and backscatter features. Their importance was estimated using an objective approach with two feature selection methods. Moreover, the study investigated how the accuracy of classification could be affected by the scale of object-based segmentation. The application of the classification method at the proper scale allowed us to observe habitat changes in the tidal inlet of the Venice Lagoon, showing that the sediment substrates located in the Chioggia inlet were subjected to very dynamic changes. In general, during the study period, the area was enriched in mixed and muddy sediments and was depleted in sandy deposits. This study presents a unique methodological approach to predictive seabed sediment composition mapping and change detection in a very shallow marine environment. A consistent, repeatable, logical site-specific workflow was designed, whose main assumptions could be applied to other seabed mapping case studies in both shallow and deep marine environments, all over the world

Stream-scanning laser system, electric sensing counter and settling grain size analysis: a comparison using reference materials and marine sediments.

Surface and deep-sea core sediments and two sets of standards were measured by three different techniques - Galai Cis I laser system, Coulter Counter TAII, and Micromeritics SediGraph 5000D - in order to compare the Galai results with the other two. The differences between the three types of measuring device turned out to be greater in sediments than in standards, and were attributed to the physical properties, shape, density and composition of the particles (complexity of the matrix). Comparison between moment statistics showed that the Galai determines coarser grain sizes than the Coulter and finer than the SediGraph, particularly as regards analysis of surface sediments. The relationships between Galai and SediGraph were estimated using analysis of variation/residuals within individual intervals. The analysis showed a higher variability of residuals for the coarser fractions (8-16 µm and 16-32 µm) with respect to the finer (2-4 µm and 4-8 µm) fractions. The <2 µm SediGraph fraction, with a cut-off at 0.49 µm, showed good correspondence with the <2.5 µm Galai analysis

Geochemistry of natural and anthropogenic fall-out (aerosol and precipitation) collected in NW Mediterranean: two different multivariate statistical approaches

The chemical characteristics of the mineral fractions of aerosol and precipitation collected in Sardinia (NW Mediterranean) are highlighted by means of two multivariate statistical approaches. Two different combinations of classification and statistical methods for geochemical data are presented. It is shown that the application of cluster analysis subsequent to Q-Factor analysis better distinguishes among Saharan dust, Background pollution (Europe-Mediterranean) and Local aerosol from various source regions (Sardinia). Conversely, the application of simple cluster analysis was able to distinguish only between aerosols and precipitation particles, without assigning the sources (local or distant) to the aerosol. This method also highlighted the fact that crust-enriched precipitation is similar to desert-derived aerosol. Major elements (Al, Na) and trace metal (Pb) turn out to be the most discriminating elements of the analysed data set. Independent use of mineralogical, granulometric and meteorological data confirmed the results derived from the statistical methods employed

The Effects of Ship Wakes in the Venice Lagoon and Implications for the Sustainability of Shipping in Coastal Waters

We analyse the impact of ship traffic in the vicinity of navigation channels in a wide shallow waterbody. The crucial hydrodynamic driver in this situation is the depression (Bernoulli) wake that may be transferred into a long-living solitary wave of depression over the shoals. The analysis considers navigation channels in the Venice Lagoon using a new large dataset of approximately 600 measured wake events associated to specific ships whose data are provided by the AIS system. Since the development of the modern industrial port and the opening of the Malamocco–Marghera channel in the late 1960s, growing pressure on the lagoon caused by ship traffic has raised concerns about its physical integrity and habitat survival. The transit of large vessels has been shown to have serious impacts on the shallow water areas adjacent to waterways. Depression wakes created by such vessels can reach significant dimensions (water level dropdown of up to 2.45 m at the channel margin), causing unusually large retreat rates of several sections of the shoreline and which may adversely affect the lagoon morphology. The wakes are analysed in relation to ship and morphological parameters. A formulation is proposed to predict wake amplitude on the basis of ship characteristics and motion